Auto-accompaniment instrument developing chord sequence based on inversion variations

Abstract

An auto-accompaniment apparatus, which selects and forms a chord that can be naturally linked with currently generated chord tones from a plurality of inversion variations, and generates the formed chord as the next accompaniment tones, is disclosed. The auto-accompaniment apparatus has an accompaniment pattern memory (1) for storing note data strings for performing an auto chord accompaniment operation on the basis of reference chords, and offset memories (3, 5) for storing tone pitch offsets of the note data with respect to the reference chord in units of chord notes of different chord names in correspondence with a plurality of chord inversion variations and root names. The plurality of offsets corresponding to the chord inversion variations are read out from the offset memories on the basis of a pre-programmed chord progression sequence or chord information detected based on play information. Of the readout offsets, an offset close to the currently generated chord tones is selected by a selector (31). The note data from the accompaniment pattern memory (1) are modified using the selected offset, and the modified data are output to a tone generator (16) as accompaniment information.

What is claimed is: 
     
       1. An auto-accompaniment apparatus comprising: accompaniment pattern memory means for storing note data strings for performing an auto chord accompaniment operation on the basis of reference chords;   offset memory means for storing tone pitch offset values of the note data with respect to the reference chords in units of chord notes of different chord names in correspondence with a plurality of chord inversion variations;   chord progression memory means for storing a chord progression sequence;   selection means for reading out a plurality of offsets corresponding to the chord inversion variations on the basis of chord name information sequentially read out from said chord progression memory means, and selecting an offset close to the currently generated chord; and   modification means for modifying the note data from said accompaniment pattern memory means using the selected offset, and outputting the modified note data as play information to tone source means.   
     
     
       2. An apparatus according to claim 1, wherein the chord name consists of chord type information and chord root information, said offset memory means comprises:   chord type offset memory means for storing tone pitch offsets in units of different chord types in correspondence with the plurality of chord inversion variations; and   chord root offset memory means for storing tone pitch offsets with respect to roots of the reference chords in units of different roots, and   said selection means selects the offset close to the currently generated chord from the offsets of the inversion variations, each of which is expressed by a sum of chord type and chord root offsets.   
     
     
       3. An apparatus according to claim 2, wherein said chord root offset memory means stores higher and lower note side offsets having an octave difference therebetween in units of different roots, and said selection means selects the offset close to the currently generated chord from sums of the offsets corresponding to the plurality of inversion variations, and higher and lower note side offsets having the octave difference therebetween.   
     
     
       4. An apparatus according to claim 3, wherein when the higher and lower note side offsets having equal pitch differences from the current offset used for developing the currently generated chord are present in the offsets to be selected, said selection means selects the lower note side offset when the current offset is positive, and   said selection means selects the higher note side offset when the current offset is negative.   
     
     
       5. An auto-accompaniment apparatus comprising: accompaniment pattern memory means for storing note data strings for performing an auto chord accompaniment operation on the basis of reference chords;   offset memory means for storing tone pitch offset values of the note data with respect to the reference chords in units of chord notes of different chord names in correspondence with a plurality of chord inversion variations;   chord name detection means for detecting chord names in a play operation from key operation information;   selection means for reading out a plurality of offsets corresponding to the chord inversion variations on the basis of chord name information sequentially detected by said chord name detection means, and selecting an offset close to the currently generated chord; and   modification means for modifying the note data from said accompaniment pattern memory means using the selected offset, and outputting the modified note data as play information to tone source means.   
     
     
       6. An apparatus according to claim 5, wherein the chord name consists of chord type information and chord root information, said offset memory means comprises:   chord type offset memory means for storing tone pitch offsets in units of different chord types in correspondence with the plurality of chord inversion variations; and   chord root offset memory means for storing tone pitch offsets with respect to roots of the reference chords in units of different roots, and   said selection means selects the offset close to the currently generated chord from the offsets of the inversion variations, each of which is expressed by a sum of chord type and chord root offsets.   
     
     
       7. An apparatus according to claim 6, wherein said chord root offset memory means stores higher and lower note side offsets having an octave difference therebetween in units of different roots, and said selection means selects the offset close to the currently generated chord from sums of the offsets corresponding to the plurality of inversion variations, and higher and lower note side offsets having the octave difference therebetween.   
     
     
       8. An apparatus according to claim 7, wherein when the higher and lower note side offsets having equal pitch differences from the current offset used for developing the currently generated chord are present in the offsets to be selected, said selection means selects the lower note side offset when the current offset is positive, and   said selection means selects the higher note side offset when the current offset is negative.